A protection device in the form of a loading space covering is known from DE 196 37 072 C1. The known loading space covering has a sheetlike structure which is mounted in a manner such that it can be wound up and unwound on a winding shaft and is provided at the end thereof which is in front in the extension direction with a dimensionally stable contour part. The contour part is assigned a supporting arm arrangement which constitutes an elongation for the contour part. By means of the supporting arm arrangement, which protrudes forwards in the winding-up direction relative to the contour part, the contour part can be fixed in the extended end position in holders on the vehicle, wherein the contour part is inevitably shifted further to the rear into a rear region within the loading space because of the elongation. The supporting arm arrangement is arranged rigidly on the contour part and remains on the contour part even in the retracted, i.e. wound-up, inoperative position of the sheetlike structure.